Examination of many cafeterias and fast food restaurants indicates that customers tend to queue up at two bottlenecks: (1) a station where special orders are placed, and (2) a cashier's station, where payment is made.
This queueing is undesirable: for (1) a given number of customers and (2) a given amount of food sold, the amount of work done by the restaurant personnel does not change appreciably whether a queue is present or absent. Thus, it can be concluded that the queues represent a waste of the customers' time.